Other than the typical ([name_f]Flick[/name_f], Flicka, [name_f]Lissie[/name_f], [name_u]Fee[/name_u], [name_u]Felice[/name_u]), can you think of anything that [name_f]Felicity[/name_f] could be shortened to?
[name_f]Issie[/name_f]
Flea (only as an affectionate family-type pet name, granted)
Ittie (see above)
[name_f]Fala[/name_f]
[name_f]Fia[/name_f]
[name_f]Fifi[/name_f]
The one [name_f]Felicity[/name_f] I was friends with in college was always just called [name_f]Felicity[/name_f] or [name_f]Feliss[/name_f]! There are a lot of nicknames available though.
I’m a [name_f]Felicity[/name_f]! My nicknames are:
[name_f]Flick[/name_f]
Fliss
[name_f]Flossie[/name_f] / [name_f]Flossy[/name_f]
[name_f]Effie[/name_f] / [name_f]Effy[/name_f]
[name_u]Fee[/name_u]
Flea
I love my name and wouldn’t change it given the choice.
Fel, a character in a book I’ve read. In Dutch it means “bright” or “fierce.”
[name_f]Liz[/name_f], from the Lic/Liss part of the name.
I really like [name_f]Felicity[/name_f] but dislike the Lissy type short forms. Once someone on nameberry (probably 5 years ago) mentioned Fizzy and I just think that is an adorable nickname for [name_f]Felicity[/name_f]!
Fliss or Flissy!
Cici
[name_m]Eli[/name_m] (Or [name_f]Elli[/name_f], depending on how you would want it pronounced)
[name_f]Lea[/name_f]
[name_f]Tia[/name_f]
I don’t know, maybe these are all too much of a stretch…just my ideas! 
[name_f]Elise[/name_f]
Cici
Lity
[name_f]Fey[/name_f]
[name_m]Eli[/name_m]
[name_f]Fifi[/name_f]
[name_m]Just[/name_m] read a book with the heroine named [name_f]Felicity[/name_f]. Her brothers called her Lissy.
the only one i’ve ever thought was cute would be Fizzy
I actually thought of [name_f]Fala[/name_f], too, but wasn’t sure if people would like it because of the dog association! I love [name_f]Flick[/name_f]/Flicka, though!
Sorry for any repeats.
[name_f]Effie[/name_f], [name_f]Letty[/name_f], [name_f]Lily[/name_f], [name_f]Lissa[/name_f], [name_f]Tilly[/name_f]
I think ‘Fizzy’ would make a cute nickname for Felicite. 
I’m not a fan of Flicka, it means ‘girl’ in my language;) I second the suggestion of [name_f]Effie[/name_f], it’s cute! Maybe [name_f]Elsie[/name_f]? It’s much of a stretch though…
My favorites
Fizzy
[name_f]Lissa[/name_f]
[name_f]Lissie[/name_f]? Either that or [name_f]Lettie[/name_f].
[name_u]Izzy[/name_u]/[name_u]Issy[/name_u] and Liddy/Lity/Litty are my favorite nns for [name_f]Felicity[/name_f], but I also like just Liss (I’m not a fan of Lissy, but I do like just Liss!), [name_u]Fee[/name_u], and some of the ones suggested that are more of a stretch, like [name_f]Lettie[/name_f], [name_f]Tilly[/name_f], and [name_f]Lily[/name_f]. I like Cici, too, but not as much as some of the others. I’ve never been a huge fan of Fliss, Lissy, or [name_f]Flick/name_f, etc.
It’s probably been mentioned before, but Cici because of the Feli(ci)ity part.
Our baby is [name_f]Felicity[/name_f]. At first we called her [name_f]Fifi[/name_f], but I got a little too many “poodle” comments. It eventually turned into Fizzy and now that’s almost the only way we refer to her, though I hope she grows into the [name_f]Felicity[/name_f] name a little more as she ages.
My favourite nickname for [name_f]Felicity[/name_f] is Fleece.